Amyloidosis is a rare disease that is underdiagnosed. About 4,500 people in the U.S. are diagnosed each year with AL amyloidosis, the most common type of amyloidosis. Most types of the condition are more likely to occur in men and in older adults. Many parts of the body can be affected by the symptoms of amyloidosis.
Amyloidosis is a protein misfolding disease. Normally, cells have many different proteins that fold into precise shapes to carry out specific tasks. When these proteins are not made correctly, they can become misfolded. Misfolded proteins tend to clump together, forming clusters of proteins known as amyloid fibrils, or amyloid deposits. These deposits build up within different organs, where they cause damage and sometimes lead to complete organ failure.
Each type of amyloidosis is caused by a different misfolded protein. Knowing which type of amyloidosis you have is important because each type requires different treatments. The following are the main types of amyloidosis.
AL amyloidosis, also called amyloid light-chain amyloidosis or primary amyloidosis, forms from abnormal light-chain proteins that are normally used to make the body’s infection-fighting antibodies.
AA amyloidosis, also called secondary amyloidosis, develops when the liver makes abnormal serum amyloid A (SAA) protein.
Hereditary ATTR amyloidosis can occur when mutations in the transthyretin (TTR) gene make abnormal TTR protein.
Hereditary non-TTR amyloidosis is caused by mutations in other genes, such as fibrinogen A alpha chain, apolipoprotein A1 and A2, gelsolin, or cystatin C.
Wild-type ATTR amyloidosis also develops from the TTR protein, but does not involve mutations in the TTR gene.
Dialysis-related amyloidosis occurs when someone has kidney disease and cannot filter and remove beta-2 microglobulin protein from the blood.
These types of amyloidosis are forms of systemic amyloidosis, meaning that amyloid deposits affect the whole body. More rarely, someone may develop localized amyloidosis, in which amyloid deposits are only found in one area, such as the eye or bladder.
Scientists don’t know exactly why some proteins begin clumping together to form amyloid deposits. However, researchers have identified some risk factors that may make a person more likely to develop amyloidosis.
AA amyloidosis is caused by underlying diseases that create inflammation. Inflammation is a process the body uses to heal itself, but too much of it can cause other health issues. When there is inflammation in the body for long periods of time, the liver starts making amyloid proteins. AA amyloidosis can be caused by diseases like:
Hereditary amyloidosis is caused by genetic mutations. Genes provide instructions that tell cells how to make proteins. When there is a change in the gene, this can sometimes lead to the creation of abnormal proteins. If you have a gene mutation that causes amyloidosis, it’s possible to pass this mutation to your children.
Receiving dialysis treatments can be a risk factor for dialysis-related amyloidosis. Dialysis is a treatment for kidney disease. Dialysis helps filter the blood, but it is not good at removing an amyloid protein called beta-2 microglobulin. People who are undergoing dialysis may develop amyloidosis when levels of this protein get too high.
Read more about the causes of amyloidosis.
Amyloidosis can sometimes lead to general symptoms, such as:
More often, amyloidosis causes specific symptoms related to the organs affected by the amyloid protein deposits. These specific symptoms are determined by the type of amyloidosis. For example, AA amyloidosis primarily affects the kidneys, leading to protein in the urine and swelling in the legs and abdomen. Hereditary and wild-type ATTR forms of amyloidosis often cause heart problems like irregular heartbeats and shortness of breath. Dialysis-related amyloidosis can lead to problems in the bones and joints, including carpal tunnel syndrome.
Learn more about amyloidosis symptoms.
Diagnosing amyloidosis early is important so you can have the best possible outcome. Initial tests will start with a physical exam, so a physician can look for symptoms of amyloidosis. Blood and urine tests can then be used to look for amyloid proteins and to test how well certain organs, like the kidneys or liver, are working.
These tests can help show whether or not amyloidosis is likely. However, the only way to officially diagnose amyloidosis is through a biopsy. During a biopsy, your doctor will use a needle to remove a small tissue sample and send it to a laboratory for further testing. This biopsy may be taken from the fat pad (abdominal fat), bone marrow, or inner lip. If your doctor wants to see whether you have damage in a particular organ, they may also want to take a biopsy from that organ.
Imaging tests can also be used to look for organ damage, joint problems, or other abnormalities. These tests may include:
When diagnosing amyloidosis, your health care team will also perform tests to determine which type you have. Biopsy samples can be tested for different types of amyloid proteins to identify which one is present in your body. If you have a hereditary form of amyloidosis, genetic testing on a blood sample can identify which gene mutation you have.
Goals of amyloidosis treatment may include slowing down or reversing the disease, treating symptoms, and preventing and fixing organ damage. The various types of amyloidosis require different treatments.
While AL amyloidosis is not a type of cancer, some cancer medications can be effective in treating it. Chemotherapy drugs are often given to treat AL amyloidosis, either alone or in combination with steroids. Additionally, targeted therapy drugs designed to identify blood cancer cells can also kill the abnormal plasma cells that cause AL amyloidosis.
If you have AA amyloidosis, treatment will involve managing the underlying condition that is causing inflammation. Reducing inflammation can help the body lower its levels of amyloid protein. The optimal treatment program will depend on which underlying condition you have. Anti-inflammatory drugs can help treat many of these conditions.
You will probably also receive additional treatments depending on your individual symptoms. For example, you may need medication to help your heart beat more efficiently or to improve your kidney function. When people have severe organ damage, they may need a transplant.
When someone has more than one health condition at the same time, the conditions are known as comorbidities. Some of these comorbid conditions, such as inflammation-causing diseases and kidney disease, can directly lead to amyloidosis. Some people with amyloidosis also have blood cancers, including multiple myeloma, Hodgkin lymphoma, and B-cell lymphoma.
Other health conditions are more likely to develop during or after amyloidosis treatment. These are known as complications. Amyloidosis can lead to disease in the kidneys, liver, heart, nervous system, gastrointestinal (digestive) system, and skin. Your doctor can help you understand your individual risk factors for developing related conditions and recommend steps to lower your risk.
Currently, amyloidosis cannot be cured. However, treatments can successfully slow down the disease and more effectively control symptoms. Your prognosis, or outlook, depends on what type of amyloidosis you have, how early you were diagnosed, and whether or not you have heart symptoms.
About 30 percent of people diagnosed with AL amyloidosis live for only a few months because they don’t get a diagnosis until their organs are already severely damaged. However, the majority of people with this subtype have a better prognosis.
Additionally, people with other types of amyloidosis also tend to have better outlooks. One study of 374 people with AA amyloidosis found the median survival period was approximately 11 years after diagnosis. Those with hereditary ATTR amyloidosis live, on average, seven to 12 years after their diagnosis.
Many new amyloidosis treatments have been developed and studied in clinical trials within the past few years. New treatments may alter the prognosis for people with amyloidosis.
Amyloidosis Condition Guide